如何從vb.net使用的app.config

Question

我需要怎麼我的當前連接轉換，並在我的vb.net項目中使用app.config所以當我轉移遷移或修改數據庫證書我不幫助連接到MySQL數據庫我需要爲我的程序重新編譯新的安裝程序。在此先感謝隊友！

這裏是我當前的連接：

Module mdlConnection 
    Public connString1 As String = "server=localhost;user id=root;password=;Database=sampleprog" 
    Public conn As MySqlConnection = New MySqlConnection(connString1) 
    Public sql As String = "" 

    Public Function ExecuteQuery(ByVal query As String) As DataTable 
     Dim sqlDT As New DataTable 
     Try 
      Dim sqlCon As New MySqlConnection(connString1) 
      Dim sqlDA As New MySqlDataAdapter(query, sqlCon) 
      Dim sqlCB As New MySqlCommandBuilder(sqlDA) 
      sqlDA.Fill(sqlDT) 
     Catch ex As Exception 
     End Try 
     Return sqlDT 
    End Function 
End Module 

（在我的mdlConnection.vb代碼）這是我的app.config裏面的配置：

Answer 1

請如下更新當前的app.config文件：

<?xml version="1.0" encoding="utf-8"?> 
    <configuration> 
     <startup> 
      <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5"/> 
     </startup> 

     <connectionStrings> 
      <add name="MySqlConnectionString" connectionString="SERVER=localhost;DATABASE=sampleprog;UID=root;PASSWORD=;" /> 
     </connectionStrings> 

    </configuration> 

然後如下修改 'mdlConnection.vb' 代碼：

Module mdlConnection 
     Public connString1 As String = ConfigurationManager.ConnectionStrings("MySqlConnectionString").ToString() 
     Public conn As MySqlConnection = New MySqlConnection(connString1) 
     Public sql As String = "" 

     Public Function ExecuteQuery(ByVal query As String) As DataTable 
      Dim sqlDT As New DataTable 
      Try 
       Dim sqlCon As New MySqlConnection(connString1) 
       Dim sqlDA As New MySqlDataAdapter(query, sqlCon) 
       Dim sqlCB As New MySqlCommandBuilder(sqlDA) 
       sqlDA.Fill(sqlDT) 
      Catch ex As Exception 
      End Try 
      Return sqlDT 
     End Function 
    End Module 

請不要忘記在您的'mdlConnection.vb'中添加命名空間'Imports System.Configuration'，並在您的解決方案中添加參考'System.Configuration'。

Answer 2

雙擊項目的「我的項目「在解決方案資源管理器中輸入從打開的窗口轉到設置選項卡。將類型更改爲連接字符串顯示在下面的截圖

或者，你可以添加以下到<configuration>打開標籤下方的app.config文件;

<configuration> 
    <connectionStrings> 
     <add name="<Desired name here>" connectionString="server=localhost;user id=root;password=;Database=sampleprog" /> 
    </connectionStrings> 
    <startup> 
    ... 
</configuration> 

然後，您可以在代碼中訪問連接字符串，如下所示。

Dim con = My.Settings.DbConnection ' provided you named your connection string DbConnection in the first step above. 

Answer 3

這裏是我的設置

這裏是我的更新mdlConnection

這裏是我的更新mdlConnection

Dim con = My.Settings.DbConnection 
Public conn As MySqlConnection = New MySqlConnection(con) 
Public sql As String = "" 

Public Function ExecuteQuery(ByVal query As String) As DataTable 
    Dim sqlDT As New DataTable 
    Try 
     Dim sqlCon As New MySqlConnection(con) 
     Dim sqlDA As New MySqlDataAdapter(query, sqlCon) 
     Dim sqlCB As New MySqlCommandBuilder(sqlDA) 
     sqlDA.Fill(sqlDT) 
    Catch ex As Exception 
    End Try 
    Return sqlDT 
End Function